Set custom locations for platform config files using plugin variables

[zdm]

PR Type

What kind of change does this PR introduce?

• Bugfix
• [ x] Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Documentation changes
• Other... Please describe:

PR Checklist

For bug fixes / features, please check if your PR fulfills the following requirements:

• Testing has been carried out for the changes have been added
• Regression testing has been carried out for existing functionality
• Docs have been added / updated

What is the purpose of this PR?

This PR adds possibility to set custom location for google-services.json and GoogleService-Info.plist using ANDROID_KEY and IOS_KEY variables.

Does this PR introduce a breaking change?

• Yes
• [ x] No

What testing has been done on the changes in the PR?

What testing has been done on existing functionality?

Other information

[zdm]

Now users can define custom locations in config.xml, or package.json:

<plugin name="cordova-plugin-firebasex">
        <variable name="ANDROID_KEY" value="resources/android/google-services.json" />
        <variable name="IOS_KEY" value="resources/ios/GoogleService-Info.plist" />
    </plugin>

If custom settings are present - they will override default hardcoded paths.

[dpa99c]

Thanks, for this - I'll merge this now but I'll rename *_KEY to *_FIREBASE_CONFIG_FILEPATH so it's clearer what the variable does from its name.

[zdm]

ok, thank you.